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Finding the Fourth Proportional to 814.42, 1,219.47 and 640.18

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Solution

The fourth proportional to 814.42, 1,219.47 and 640.18 is: 958.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    814.42 : 1,219.47 = 640.18 : x
  2. Step 2: Convert to fraction form
    814.42/1,219.47 = 640.18/x
  3. Step 3: Cross multiply
    814.42x = 1,219.47 × 640.18
  4. Step 4: Simplify right side
    814.42x = 780,680.30
  5. Step 5: Solve for x
    x = 780,680.30/814.42
  6. Step 6: Final answer
    x = 958.57

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.